Question

Which of the following gases requires the least temperature for liquefaction?

• A. Ammonia
• B. Helium
• C. Hydrogen
• D. Nitrogen

Answer 1

The correct option is B Helium

Higher the intermolecular forces, higher the temperature for liquefaction. Helium has the least intermolecular forces while ammonia has highest intermolecular forces so helium has the least temperature for liquefaction.

The temperature required for liquefaction of:

Ammonia: $-33{}^{o}C$

Helium: $-{268}^{o}C$

Hydrogen: $-{252.87}^{o}C$

Nitrogen: $-{147}^{o}C$

Hence, option B is correct.